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H. W. LATHROP.

Improvement in Apparatus for Separating Meta|s..

No, 128,404, Patented-June 25,1872.

Witnesses VE 7V@ I" Mow u in M v -y hh mm k UNITED STATES A'INT Orrrcn.

HARVEY w. 'LATHROP, or BALTIMORE, MARYLAND.

IMPROVEMENT IN APPARATUS FOR SEPARATING METALS Specification forming part of Letters Patent No. 128,404, dated June 25, 1872.

the several metals by dropping the powder;-

through a hopper into a box or sluice, through which a gentle current of water is led, and under which box, at suitable distances, side troughs are arranged under openings or slits in the bottom of the box, so that the different metals falling into the current are carried a greater or less distance from the vertical line of their fall, according to their different gravities, before they reach the bottom of the sluice,

and are washed through the slits into the dif-. ferent troughs, and. are thus sorted according to their different gravities.

In the accompanying drawing, Figure 1 represents a longitudinal vertical section of my improved apparatus for separating the ores or metals; and Fig. 2 represents a vertical crosssection of the same in line a: m, Fig. 1.

A sluice-box, a, of any suitable material and length, is provided at one end with a hopper, 1), through which the powdered ores are dropped into a current of water led into the sluice-box a; or the sluice-box may be placed in a suitable stream having a gentle current. In regions where water is scarce, as is the case in many mining districts, a pump or other mechanism may be used to return the water after it has passed through the box a to the end under the hopper, and. thus reissue the water over and over again as long as possible. In the bottom of the sluice-box a are formed slits or openings 0, at suitable distances from but not high enough to prevent lighter partieles of earth, quartz, or dross from being washed away. Secured across the under side of the bottom of the sluice-box a, and one under each slit or opening 0, are inclined troughs 0, larger at their outer ends, through which the particles of metal are delivered by the water as they are washed through the slits or openings '0. I

The powdered mass of ores, &c., being thrown into the hopper b, the diiierent particles of metals, &c., drop quicker or slower, according to their respective 'gravities, until they come in contact with the current of water, when they deviate from the vertical line of their fall by reason of the force of the current. But even in the current the different gravity of the particles will cause them to come to the bottom of the box nearer to or further from the vertical line of the hopper from which they fell; in other words, the current will carry the lighter particles further along in the box before they reach the bottom and are arrested by the ridges 01 than it will carry the heavier particles, which will reach the bottom sooner than the lighter ones. Supposing gold to be the heaviest oresof the crushed metals, and

that it would reach the bottom of the sluice in front of the first ridge d; lead, supposing it to be the next heaviest, would go into the next opening 0; silver, the next; copper, the next; and so on according to their different gravities; and it will be understood that the openings f, shielded by pieces 9, and formed v in any suitable manner, through which openings'water may be admitted to clear the hopper if it should be clogged, or to admit the water if the box is used in a stream, and the stream should rise'beyond the top of the box a.

0 at suitable distances in its bottom, ridges d, V

and troughs e, and arranged to be used with a current of water, the force of the current and difference in gravity of the difierent metals operating to separate and deliver the several metals separately from each other, essentially in the manner described.

The above specification of my improvement in mineral-separators signed this 26th day of February, 1872.

HARVEY W. LATHROP.

Witnessesz' A. E. H. JOHNSON,

- ALEXR. A. O. KLAUCKE. 

